Apparatus for coating pipes



Nov. 20, 1956 F. o. Hess APPARATUS FoR COATING PIPES 2 Sheets-Sheet 1 Filed June 6, 1951 \\\\l naar-..

ATTORNEY.

F. O. HESS APPARATUS FOR COATING PIPES Filed June 6, 1951 INVENTOR. FREDERIC O. HESS 1 ATTORNEY.

Unite rates Patent O APPARATUS FR COATING PIPES Frederic 0. Hess, Philadelphia, Pa., assigner to Selas Corporation of America, Philadelphia, Pa., a corporation of Pennsylvania Application June 6, 1951, Serial No. 230,166

Claims. (Cl. 118-64) The present invention relates to the coating of elongated metal bodies, and more particularly to the coating or galvanizing of pipes, tubes and the like. In describing the invention, reference will be made to the galvanizing of pipes, although it will be apparent to those skilled in the art that other elongated bodies can be coated, and that the coating treatment can be for processes other than galvanizing.

In the galvanizing of metal it is necessary to have a clean surface in order to obtain a good bond. It is also desirable, if not necessary, to have the metal to be coated at a temperature at least equal to the temperature of the coating bath.

It is an object of the present invention to provide a method and apparatus for galvanizing continuously pipe and the like. It is a further object of the invention to provide a method and apparatus -for supplying pipes one after the other in end to end relation to a furnace in which they can be heated in an non-oxidizing atmosphere, and transferring the pipes one after the other from the furnace, through an enclosed passageway to the galvanizing bath. The pipes are removed from the bath either transversely or axially to a place of storage.

In practicing the invention, there is provided a supply table from which pipes are moved one after the other in an axial direction into a furnace. The furnace is of the mule type in which there is a reel having portions at the periphery thereof to receive the individual pipes. This reel is rotated while the pipes are being heated in a non-oxidizing atmosphere, to move the pipes through substantially 360 from the receiving position to a discharge position from which they are removed axially in the same direction that they travelled into the furnace. The pipes move through an enclosed passage in which they are protected from the air directly into a galvanizing bath. Means are provided to remove the coated pipes from the bath to a point of storage.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific object attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described preferred embodiments of the invention.

In the drawings,

Figure l is a side View, partly in section, of the general arrangement of the galvanizing system,

Figure 2 is an enlarged side view of the furnace, partly in section,

Figure 3 is a sectional View of the furnace taken on line 3-3 of Figure 2,

Figure 4 is a section View showing the loading apparatus taken on line 4-4 of Figure 2, and

Figure 5 is a section taken on line 5 5 of Figure l to show apparatus for discharging the pipe from the galvanizing tank.

Referring to Figure l, there is shown the general ar- 'ice rangement of the apparatus by means of which pipe, tubing, rods and the like, may be moved substantially continuously from a point of supply to a point of delivery at which the pipes are galvanized. There is shown a supply station 1 from which the pipes are -fed to a furnace 2.. As the pipes are discharged from the furnace, they are supplied to a galvanizing tank 3 having a discharge apparatus 4 cooperating therewith. The supply table and the furnace are shown as being at a slight angle to the horizontal. This arrangement permits the pipes to go in the galvanizing tank at an angle so that any gas in the interior of the pipes will be discharged as the galvanizing material flows upwardly through the bore of the pipe.

The supply station 1 consists of a table upon which the pipes are laid and includes a portion 5 that extends substantially to the entrance of the furnace. This portion is provided with a series of rollers 6 by means of which the pipe can be fed axially into a pair of continuously rotating pinch rollers 7 at the entrance of the furnace. The furnace itself includes a substantially cylindrical structure 8 made of refractory materials such as iirebricks that are backed up with insulating material. Surrounding the refractory structure, in the usual manner, is a sheet metal backing 9. Also, in accordance with usual furnace practice, the entire furnace is supported rigidly in place by structural steel members 11. The refractory material 8 has located at spaced points along its length and around the interior thereof, a plurality of burners 12 by means of which the furnace is heated. These burners can be of any suitable type, but are shown herein as being of the type disclosed in Hess Patent 2,215,079, issued September 17, 1940. Each of these burners includes a refractory block that has a substantially cup-shaped opening in the face thereof. A combustible mixture of gas and air is supplied through suitable piping to the base of the cup where it is discharged in a series of substantially radially directed jets to be burned along the cup surface and heat the latter to incandescence. Radiant heat as well as convection heat from the hot gases of combustion bring the furnace to the desired temperature. The various burners are connected by suitable piping and manifolds (not shown) so that the burners can be controlled either singly or in groups to heat uniformly the entire area of the furnace chamber.

Located concentrically within the furnace chamber is a cylindrical muie 13 made of suitable heat resisting alloy steel. This mufie is provided with an inlet corridor 14 leading from the vfeed roll 7 and through which the pipes are moved into the mufiie where they are heated. The various pipes to be heated are moved into the mule in an axial direction and are then moved transversely around the inner surface of the mule while they are being heated. Thereafter, the pipes are moved axially from the furnace to the galvanizing bath. To this end, there is provided in the mufe, an elongated hollow shaft 1S the ends of which are closed by discs 16. Each of these discs has a projection 17 extending axially therefrom through an opening in the mufe. The openings in the ends of the mule through which the projections extend are closed by stuiling boxes 1S, and the ends of the projections 17 are received iu bearings 19 in which they can rotate. Rotation is accomplished intermittently by any suitable means that is shown herein as including a gear 21 on the end of one of the trunnions 17 which gear is driven in any suitable manner.

The shaft 15 is used to support a reel that receives the pipes and moves them around the interior of the muie. To this end, the shaft is provided with a plurality of radially extending anges 22 to which are attached by bolts 24 a plurality of substantially T-shaped supporting members 23. Each of these members is provided on its periphery with a plurality of notches that are aligned with similar notches on the other members. The aligned notches each receive a substantially semi-circular guiding and holding channel 25 into which the pipes are moved by the pinch roller 7. The muflle 13 is provided at its oppositeend, on the right end of Figure 2 of the drawing, with an outlet corridor 26 through which the pipes are discharged into an enclosed passageway 27 leading to the galvanizing bath. A means is provided at the entrance of the passageway 427 for moving the pipes axially into the vgalvanizing bath which my take the form of pinch rollers,

but is shown herein as being a continuously driven magnetic roller 28. During the time that the pipes are being heated, they are preferably protected from the effects of oxygen in the yair by introducing into the muffle a suitable neutral or reducing atmosphere. To this end, there is provided apipe 30 through which the atmosphere may be discharged into the muflle.

, The inlet corridor 14 and the means `for loading and unloading the pipes in the muie are best shown in Figure 4. Referring to that figure, it will be seen that the shaft 15 has been rotated to a position in which one of the channels 2S is axially aligned with the pinch rollers 7. There are also shown in this figure three of the pipes indicated at A, B and C. The pipe A is in the unloading position which is -adjacent to and parallel to the position in which it was loaded into the muflle. The pipe is unloaded from the muffle by moving it while it is in the position A axially until the other end thereof is in engagement with the drive roller 28. For this purpose there is provided a plunger 29 on the end of a piston rod 31 that is received in a cylinder 32. When the piston rod is moved to the right in Figure 4, the pipe will be moved axially so that it can be removed by the roller 28 from the muffle. The pipe shown at B is in the loading position. This pipe is moved either manually or automatically until its right end is grasped by the pinch rollers 7. The pinch rollers, driven by the shafts 33, will then move the pipe axially into the channel 25 that is aligned therewith until the pipe is in the dotted line position indicated at D. The pipe shown at C is the pipe that was last moved into the mule by the pinch rollers. It will be noted that the left end of this pipe is still in the corridor 14, and that its end has not been moved far enough to clear the end of the mule. The pipe is pushed further into the mufe until it is in an axial position corresponding to the position A by a means of a plunger 34 that is on the end of a piston rod 35 received in a cylinder 36. The plunger 34 will move the ,pipe to the right until Vits right end hits a stop 3'7 which is shown in Figure 2 of the drawing. lt is noted that this stop extends around the interior of the end of the Inutile exceptacross that portion of the muflle through which the outlet corridor 26 is formed.

.In the operation `of the system thus far described, the shaft 1S and the parts carried thereby are moved to a position in which the channels 25 are lined up as shown in Figure 4 of the drawing. The position that these channels assume with respect to the muffle is also shown in Figure 3 of the drawing. While the shaft 15 and the reel carried thereby are stationary in the position of Figure 4, fluid is permitted to flow into the cylinders 32 and 36, thereby moving the plungers 29 and 34 respectively to the right in that ligure. Simultaneously the pipe indicated at B is moved into the pinch rollers so that they can move it into the furnace, By the time the pipe B vis completely in the furnace, the pipe at A will be removed from the furnace by roller 2S, and the pipe at C will have been rnoved up against the stop 37. The

kplungers 2S and 34 are then retracted to the position shown in Figure 4 and the shaft 15 is again rotated to bring the parts carried thereby into a position for an- -other pipe to b'e discharged from the furnace while a -new pipe is being moved linto the furnace. The inter- ?rnittent rotation of the reel :and the operation ofthe pipe moving plungers may be obtained by any suitable operating mechanism.

It will be noted that the mutle is closed except for the exit corridor 26 and the entrance corridor 14. As Will be pointed out below, none of the atmosphere introduced into the mule can be lost through the passageway 27. There is a continual leakage of the atmosphere, however, through the entrance corridor 14, both between the pinch rollers 7 during the time that no pipe is between these rollers, and through the bore of the pipe itself'as one is being moved into themuflle. This leakage, however, is necessary since the atmosphere within the mule is used to purge the bore of the pipes so that any oxygen in the pipes will be removed before they are heated. This does away with the possibility of the interior of the pipes becoming oxidized. n

As the pipes leave the furnace, they pass through the passage 27 into the galvanizing tank 3. The tank, as shown in Figure l, has a shallow portion 38 extending to the left in that figure, almost to the exit of the furnace. The level of the galvanizing bath is indicated at 39 and it will be seen that the pipes enter the bath prior to the time that they leave the passage 27. In this way, the pipes are protected from the oxidizing effects of the air between the time they are heated until they are completely immersed in the bath. During their travel from the furnace -to the bath, the pipes are guided on a series of rollers 41 sosthat each pipe moves through a path which is at anangle to the horizontal. In this fashion, any of the atmosphere from the furnace that remains in the pipe is forced out of the same as the galvanizing material ows through the center of the pipe, as well as along the surface thereof.

The galvanizing tank is shown as being constructed in accordance with usual furnace practice. There is provideda metal tank 42 in which the molten zinc for the `bath is contained. Around this tank is the usual insulating refractory material 43. It will be seen from an inspection of Figures l and 5 that portions of the refractory are spaced from the outer surface of the tank to form a combustion kspace into which burners 44 are directed. These burners are shown herein as being similar to the burners that were used in the furnace. The heat from these burners is used to melt and to maintain liquid the material with which'the pipes are coated.

The pipes can be removed from the galvanizing bath in any desired fashion. If there is room enough, the pipes can kbe moved axially 'through and out of the bath to a point v.of storage. As shown herein, however, the pipes are moved transversely from the bath by apparatus, the details of which are shown more or less diagrammatically in `Figure 5. There is provided a framework 45 extending above the galvanizing tank, the upper members on the ends of which form a pair of rails 46. A carriage 47, provided with rollers or wheels 43 riding on the rails 46, is moved back and forth transversely of the tank 3 by means of cables 49 that are guided over pulleys 51. These pulleys are mounted on a shaft 52 that is suitably journaled on the framework, and which is rotated periodically in opposite directions by means of a motor 53. A second carriage 54 is carried by the carriage 47 and is movable vertically with respect thereto. The second carriage is supported by a pair of cables 55 that-are guided over pulleys r56 on a shaft '57 that is journaled for rotation on the carriage V47'. The shaft is rotatedperiodically in opposite directions by means of Va motor 58 to raise and lower the carriage 54. Carriage 54 is guided for vertical move ment with respect to the carriage 47 by a number of guide bars 59 that are fastened to the carriage 54 and which are received in suitable journals provided lon the carriage 47.

Depending from the lower carriage 54 are four pairs of pushermembers 61, 62, 63 and 64. These members serve to engage the pipes that are in the bath and move them periodically and in steps toward the left in Figure 5.

D The pipes, as they move into the bath along rollers 41, come to rest over a pair of supporting members 65 and 66 that extend across the galvanizing tank at spaced points therein. Each of these supporting members is provided with four transversely spaced stations into which the pipes are pushed as they move from the right hand position shown in Figure to the discharge table 67.

In the operation of the discharge mechanism, with the parts in the position shown in Figure 5 of the drawing, motor 53 will be rotated to move the carriages 47 and 54 to the left suiciently to move each of the pipes in the tank one station to the left and to move the pipe in the last station on the left down the discharge table. Motor 58 will then be energized for rotation in a direction to raise carriage 54 so that the pusher members are above the levels of the pipe. Motor 53 will then be rotated in a direction to permit the carriage to move to the right until the pusher members are slightly to the right of the pipes or in a position above that shown in Figure 5, after which motor 58 is energized to lower carriage 54 so that the parts are in the position shown. This series of operations is repeated periodically. During the time that the carriages are in their right hand position, another pipe will have been discharged from the furnace into the galvanizing tank.

It will be noted from Figure 5 of the drawing that the supporting members 65 and 66 are so positioned in the tank that they will receive the pipes in their inclined position as they move into the tank. In the second station that the pipes are moved into, it will be noted that the pipes are at a smaller angle to the horizontal. In the third station, the pipes are substantially horizontal while in the last station, the pipes are above the level 39 of the bath and are moved so that they have been tilted slightly in the opposite direction. At this point, the galvanizing material in the interior of the pipe will flow therefrom so that the bore of the pipe is open. It may be necessary to use high pressure steam or air to blow the molten material from the center of the pipe. In the last position assumed by the pipe, it is horizontal and will roll down the slightly inclined discharge platform 67.

In the arrangements shown, the burners are adjusted so that the furnace outside of the mufe is approximately 1200 F. The temperature in the mufe will be approximately 900 F. and the pipes will be in the furnace long enough to heat them to a temperature of approximately 850 F. This temperature is slightly above the melting point of the zinc in the galvanizing bath which is approximately 840 F. Therefore, it will be seen that the pipes are heated to a temperature substantially the same as, but slightly above, the temperature of the zinc so that they can impart a small amount of heat thereto, rather than remove heat from the bath. With an apparatus of this type, in which the rotating member will hold 42 pipes 2l feet long, approximately 630 pieces of pipe, 1/2 in diameter, can be heated per hour, or one piece every ten seconds.

From the above description, it will be seen that the invention shows a system wherein pipes to be galvanized are moved in an axial direction from a supply point into the galvanizing tank. Some place along this path of movement, the pipes are moved transversely while they are being heated. Means is provided to protect the pipes from the oxidizing elect of the atmosphere and, if necessary, to heat them in a reducing atmosphere in order to remove surface oxidation so that pipes are clean when they are moved into the galvanizing bath. This insures that there will be a good bond between the pipes and the zinc. The present arrangement is one in which the pipes. may be handled conveniently and with a minimum amount of manipulation. Furthermore, the generally axial ow of the pipes requires less floor space for a given Weight 0f pipe to be heated than is used or required by conventional galvanizing apparatus.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention, as set worth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. Apparatus for galvanizing pipes comprising in combination a furnace having a substantially cylindrical closed chamber therein, means to heat said chamber located around the exterior thereof, means forming an entrance at one end of said chamber and an exit, displaced circumferentially from said entrance, at the opposite end of said chamber, rotary conveying means in said chamber to move pipe circumferentially from said entrance to said exit whereby the pipe can be heated as it is moving, a galvanizing tank located axially beyond the exit of said chamber, a tunnel extending between said exit and said tank below the level of zinc therein, and means to move pipe axially into said chamber and axially from said chamber through said tunnel into said tank.

2. The combination of claim 1 including means to supply a non-oxidizing atmosphere to said chamber and said tunnel.

3. Apparatus for galvanizing pipes comprising in combination a furnace having means to heat the same, a closed chamber in said furnace and heated thereby, means to move pipe axially into said chamber, means in said chamber to move pipe laterally from the position in which it enters said chamber to a second position displaced therefrom, means to move pipe in said second position axially from said chamber in the same direction as its rst mentioned movement, a galvanizing tank adapted to contain molten zinc located in the path of movement of the pipe as it leaves the chamber to receive the pipe, a tunnel extending between said chamber where the pipe leaves said chamber to a point in said tank below the level of the zinc therein, and means to introduce a protective atmosphere in said chamber and tunnel -to protect the pipe from the time it enters said chamber until it is beneath the zinc in said tank.

4. The combination of claim 3 in which said chamber is cylindrical in shape and in which said means in said chamber to move the pipe laterally operates to move the pipe circumferentially substantially in engagement with the inner surface of said chamber.

5. Apparatus for galvanizing pipes comprising in combination an elongated, closed chamber having an entrance in one end and an exit, displaced from said entrance, in the other end, a galvanizing tank adapted vto contain molten zinc axially aligned with said exit, means forming a tunnel extending between said exit and a point below the level of the zinc in said tank, means to move pipe axially into said chamber, means to displace pipe laterally in said chamber from the entrance to the exit, means to move pipe axially from said chamber through said exit and through said tunnel into said tank, and means surrounding said chamber to heat the same.

References Cited in the file of this patent UNITED STATES PATENTS 947,440 Greenfield Ian. 25, 1910 1,430,651 Herman Oct. 3, 1922 2,141,163 Braun Dec. 27, 1938 2,216,519 Quarnstrom Oct. 1, 1940 2,371,335 Kritschner Mar. 13, 1945 2,642,834 Pearson June 23, 1953 

